Container assemblies with releasable locking feature

ABSTRACT

A container assembly comprises a first container and a second container. The first container includes a first continuous body portion and a first rim. The rim has a first plurality of ribs projecting generally upwardly therefrom such that first spaces are formed between adjacent ribs. The second container includes a second continuous body portion and a second rim. The rim has a second plurality of ribs projecting generally upwardly therefrom such that second spaces are formed between adjacent ribs. The second rim and the first rim are shaped substantially the same. The first container and the second container are adapted to be releasably lockable to each other by fitting the first plurality of upwardly-projecting ribs into respective second spaces and fitting the second plurality of upwardly-projecting ribs into respective first spaces. The first container may be shaped substantially the same as the second container.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application of U.S. patentapplication Ser. No. 10/277,303, filed Oct. 22, 2002.

FIELD OF INVENTION

The present invention relates generally to containers. Moreparticularly, the present invention relates to releasably lockablecontainer assemblies and containers therein.

BACKGROUND OF THE INVENTION

The use of inexpensive polymeric, paper or metal packaging containershas become popular, especially for preparing and serving various foodproducts. Polymeric, paper and metal containers generally have been usedfor heating the food product(s) disposed therein. These containerstypically comprise a cover or lid and a base.

It would be desirable to have a container that would be easy for thecustomer to close and open. It would also be desirable to provide acontainer that is releasably lockable and prevents or inhibits material,such as liquid, from leaving the container. It would be desirable for acontainer to function without necessarily having a lid, but if a lid isdesired to form a container assembly, a customer would be able to makesuch an assembly.

It would also be desirable to provide a container that is easy tomanufacture and reduces the inventory requirement of customers thatpurchase the containers. It would also be desirable to produce acontainer that stacks efficiently so as to reduce the costs associatedwith shipping and storing the containers.

SUMMARY OF THE INVENTION

According to one embodiment, a container assembly comprises a firstcontainer and a second container. The first container includes a firstcontinuous body portion and a first rim. The first rim encompasses andprojects laterally outwardly from the first body portion. The rim has afirst plurality of ribs projecting generally upwardly therefrom suchthat first spaces are formed between adjacent ribs. The first pluralityof ribs have a first sidewall and a second sidewall. A generally flatsurface encompasses and bridges the first and second sidewalls of thefirst plurality of ribs. The first plurality of ribs have a roundedportion that transitions from the generally flat surface towards thefirst body portion. The second container includes a second continuousbody portion and a second rim. The second rim encompasses and projectslaterally outwardly from the second body portion. The rim has a secondplurality of ribs projecting generally upwardly therefrom such thatsecond spaces are formed between adjacent ribs. The second plurality ofribs have a third sidewall and a fourth sidewall. A generally flatsurface encompasses and bridges the third and fourth sidewalls of thesecond plurality of ribs. The second plurality of ribs have a roundedportion that transitions from the generally flat surface towards thefirst body portion. The first container is shaped substantially the sameas the second container. The first container and the second containerare adapted to be releasably lockable to each other by fitting the firstplurality of upwardly-projecting ribs into respective second spaces andfitting the second plurality of upwardly-projecting ribs into respectivefirst spaces.

According to one process, a container assembly is formed that comprisesproviding a first container that includes a first continuous bodyportion and a first rim. The first rim encompasses and projectslaterally outwardly from the first body portion. The rim has a firstplurality of ribs projecting generally upwardly therefrom such thatfirst spaces are formed between adjacent ribs. A second container isprovided that includes a second continuous body portion and a secondrim. The second rim encompasses and projects laterally outwardly fromthe second body portion. The rim has a second plurality of ribsprojecting generally upwardly therefrom such that second spaces areformed between adjacent ribs. The first container is shapedsubstantially the same as the second container. One of the firstcontainer and the second container is flipped such that the firstcontainer and second container are generally aligned and the first rimand the second rim are adjacent to each other. The first plurality ofupwardly-projecting ribs is fit into respective second spaces and thesecond plurality of upwardly-projecting ribs is fit into respectivefirst spaces such that the first container and the second container arereleasably lockable to each other.

According to another embodiment, a container assembly comprises a firstcontainer and a second container. The first container includes a firstcontinuous body portion and a first rim. The first rim encompasses andprojects laterally outwardly from the first body portion. The rim has afirst plurality of ribs projecting generally upwardly therefrom suchthat first spaces are formed between adjacent ribs. The second containerincludes a second continuous body portion and a second rim. The secondrim encompasses and projects laterally outwardly from the second bodyportion. The rim has a second plurality of ribs projecting generallyupwardly therefrom such that second spaces are formed between adjacentribs. The second rim and the first rim are shaped substantially thesame. The first container and the second container are adapted to bereleasably lockable to each other by fitting the first plurality ofupwardly-projecting ribs into respective second spaces and fitting thesecond plurality of upwardly-projecting ribs into respective firstspaces.

According to another process, a container assembly is formed thatcomprises providing a first container that includes a first continuousbody portion and a first rim. The first rim encompasses and projectslaterally outwardly from the first body portion. The rim has a firstplurality of ribs projecting generally upwardly therefrom such thatfirst spaces are formed between adjacent ribs. A second container isprovided that includes a second continuous body portion and a secondrim. The second rim encompasses and projects laterally outwardly fromthe second body portion. The rim has a second plurality of ribsprojecting generally upwardly therefrom such that second spaces areformed between adjacent ribs. The second rim and the first rim areshaped substantially the same. One of the first container and the secondcontainer is flipped such that the first container and second containerare generally aligned and the first rim and the second rim are adjacentto each other. The first plurality of upwardly-projecting ribs is fitinto respective second spaces and the second plurality ofupwardly-projecting ribs is fit into respective first spaces such thatthe first container and the second container are releasably lockable toeach other.

According to a further embodiment, a container assembly comprises afirst and second container. The first container includes a firstcontinuous body portion and a first rim. The first rim encompasses andprojects laterally outwardly from the first body portion. The rim has afirst plurality of upwardly projecting features with first spaces beingformed between adjacent upwardly projecting features. The secondcontainer includes a second continuous body portion and a second rim.The second rim encompasses and projects laterally outwardly from thesecond body portion. The rim has a second plurality of upwardlyprojecting features with second spaces being formed between adjacentupwardly projecting features. The second rim and the first rim areshaped substantially the same. The first container and the secondcontainer are adapted to be releasably lockable to each other by fittingthe first plurality of upwardly projecting features into respectivesecond spaces and fitting the second plurality of upwardly projectingfeatures into respective first spaces.

According to yet another embodiment, a container to be used in acontainer assembly comprises a continuous body portion and a rim. Therim encompasses and projects laterally outwardly from the body portion.The rim has a first plurality of ribs projecting generally upwardlytherefrom such that first spaces are formed between adjacent ribs. Therim is adapted to be releasably lockable by fitting the first pluralityof ribs and first spaces into respective second spaces and secondplurality of ribs of a second container. The second spaces and thesecond plurality of ribs are shaped substantially the same as respectivefirst spaces and first plurality of ribs.

According to yet a further embodiment, a container assembly comprises afirst and second container. The first container includes a firstcontinuous body portion and a first rim. The first rim encompasses andprojects laterally outwardly from the first body portion. The rim has afirst plurality of ribs projecting generally upwardly therefrom suchthat first spaces are formed between adjacent ribs. The second containerincludes a second continuous body portion and a second rim. The secondrim encompasses and projects laterally outwardly from the second bodyportion. The rim has a second plurality of ribs projecting generallyupwardly therefrom such that second spaces are formed between adjacentribs. The first container is shaped substantially the same as the secondcontainer. The first container and the second container are adapted tobe releasably lockable to each other by fitting the first plurality ofupwardly-projecting ribs into respective second spaces and fitting thesecond plurality of upwardly-projecting ribs into respective firstspaces. The first rim and the second rim are adapted to form a seal.

According to still yet another embodiment, a container assemblycomprises a first container and a second container. The first containerincludes a first continuous body portion and a first rim. The first rimencompasses and projects laterally outwardly from the first bodyportion. The rim has a first plurality of ribs projecting generallyupwardly therefrom such that first spaces are formed between adjacentribs. The first plurality of ribs have a first sidewall and a secondsidewall. A generally flat surface encompasses and bridges the first andsecond sidewalls of the first plurality of ribs. The first plurality ofribs have a rounded portion that transitions from the generally flatsurface towards the first body portion. The second container includes asecond continuous body portion and a second rim. The second rimencompasses and projects laterally outwardly from the second bodyportion. The rim has a second plurality of ribs projecting generallyupwardly therefrom such that second spaces are formed between adjacentribs. The second plurality of ribs have a third sidewall and a fourthsidewall. A generally flat surface encompasses and bridges the third andfourth sidewalls of the second plurality of ribs. The second pluralityof ribs have a rounded portion that transitions from the generally flatsurface towards the second body portion. The first container is shapedsubstantially the same as the second container. The first container andthe second container are adapted to be releasably lockable to each otherby fitting the first plurality of upwardly-projecting ribs intorespective second spaces and fitting the second plurality ofupwardly-projecting ribs into respective first spaces.

According to still yet a further embodiment, a container assemblycomprises a first container and a second container. The first containerincludes a first continuous body portion and a first rim. The first rimencompasses and projects laterally outwardly from the first bodyportion. The rim has a first plurality of ribs projecting generallyupwardly therefrom such that first spaces are formed between adjacentribs. The first plurality of ribs have a first sidewall and a secondsidewall. A generally flat surface encompasses and bridges the first andsecond sidewalls of the first plurality of ribs. The first plurality ofribs have a rounded portion that transitions from the generally flatsurface towards the first and second sidewalls. The second containerincludes a second continuous body portion and a second rim. The secondrim encompasses and projects laterally outwardly from the second bodyportion. The rim has a second plurality of ribs projecting generallyupwardly therefrom such that second spaces are formed between adjacentribs. The second plurality of ribs have a third sidewall and a fourthsidewall. A generally flat surface encompasses and bridges the third andfourth sidewalls of the second plurality of ribs. The second pluralityof ribs have a rounded portion that transitions from the generally flatsurface towards the third and fourth sidewalls. The first container isshaped substantially the same as the second container. The firstcontainer and the second container are adapted to be releasably lockableto each other by fitting the first plurality of upwardly-projecting ribsinto respective second spaces and fitting the second plurality ofupwardly-projecting ribs into respective first spaces.

According to yet again another embodiment, a container to be used in acontainer assembly comprises a continuous body portion and a rim. Therim encompasses and projects laterally outwardly from the body portion.The rim has a first plurality of ribs projecting generally upwardlytherefrom such that first spaces are formed between adjacent ribs. Thefirst plurality of ribs have a first sidewall and a second sidewall anda generally flat surface that encompasses and bridges the first andsecond sidewalls. The first plurality of ribs have a rounded portionthat transitions from the generally flat surface towards the first bodyportion. The rim is adapted to be releasably lockable by fitting thefirst plurality of ribs and first spaces into respective second spacesand second plurality of ribs of a second container. The second spacesand the second plurality of ribs are shaped substantially the same asrespective first spaces and first plurality of ribs.

According to yet again a further embodiment, a container to be used in acontainer assembly comprises a continuous body portion and a rim. Therim encompasses and projects laterally outwardly from the body portion.The rim has a first plurality of ribs projecting generally upwardlytherefrom such that first spaces are formed between adjacent ribs. Thefirst plurality of ribs have a first sidewall and a second sidewall anda generally flat surface that encompasses and bridges the first andsecond sidewalls. The first plurality of ribs have a rounded portionthat transitions from the generally flat surface towards the first andsecond sidewalls. The rim is adapted to be releasably lockable byfitting the first plurality of ribs and first spaces into respectivesecond spaces and second plurality of ribs of a second container. Thesecond spaces and the second plurality of ribs are shaped substantiallythe same as respective first spaces and first plurality of ribs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a container to be used in one embodiment of theinvention;

FIG. 2 is a top view of the container of FIG. 1;

FIG. 3 is an enlarged cross-sectional view taken generally along linesFIG. 3-FIG. 3 in FIG. 2;

FIG. 4 is an enlarged top view of generally circular region FIG. 4 ofFIG. 2;

FIG. 5 is a perspective view of generally circular region FIG. 5 of FIG.2 depicting two adjacent projecting ribs;

FIG. 6 is a sectional view of generally circular region FIG. 6 of FIG. 1according to one embodiment.

FIG. 7 a is a side view of a container assembly in a releasably lockableposition using the container of FIG. 1 and a second identical containerof FIG. 1 according to one embodiment of the present invention;

FIG. 7 b is a top view of the container assembly of FIG. 7 a;

FIG. 8 is an enlarged cross-sectional view taken generally along linesFIG. 8-FIG. 8 in FIG. 7 b;

FIG. 9 is a side view of a container to be used in another embodiment ofthe invention;

FIG. 10 is a top view of the container of FIG. 9;

FIG. 11 is an enlarged top view of generally circular region FIG. 11 ofFIG. 10;

FIG. 12 is a perspective view of generally circular region FIG. 11 ofFIG. 10 depicting two adjacent projecting ribs;

FIG. 13 is an enlarged cross-sectional view taken generally along linesFIG. 13-FIG. 13 in FIG. 12;

FIG. 14 a is a side view of a container assembly in a releasablylockable position using the container of FIG. 9 and a second identicalcontainer of FIG. 9 according to another embodiment of the presentinvention;

FIG. 14 b is a top view of the container assembly of FIG. 14 a;

FIG. 15 is an enlarged cross-sectional view taken generally along linesFIG. 15-FIG. 15 in FIG. 14 b;

FIG. 16 a is a top view of yet another container to be used in thepresent invention; and

FIG. 16 b is an enlarged cross-sectional view taken generally alonglines FIG. 16 b-FIG. 16 b in FIG. 16 a.

FIG. 17 is a side view of a container to be used in a further embodimentof the invention;

FIG. 18 is a top view of the container of FIG. 17;

FIG. 19 is an enlarged cross-sectional view taken generally along linesFIG. 19-FIG. 19 of FIG. 18;

FIG. 20 is an enlarged perspective view of generally circular regionFIG. 20 of FIG. 18 depicting two adjacent projecting ribs;

FIG. 21 is an enlarged top view of generally circular region FIG. 21 ofFIG. 18.

FIG. 22 is a side view of a container assembly in a releasably lockableposition using the container of FIG. 17 and a second identical containerof FIG. 17 according to one embodiment of the present invention;

FIG. 23 is a top view of the container assembly of FIG. 22;

FIG. 24 is an enlarged cross-sectional view taken generally along linesFIG. 24-FIG. 24 of FIG. 23

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof have been shown by wayof example in the drawing and will herein be described in detail. Itshould be understood, however, that it is not intended to limit theinvention to the particular forms disclosed but, on the contrary, theintention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the invention as defined by theappended claims.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Referring to FIGS. 1-5, a container (e.g., plate 10) to be used in oneembodiment of the present invention is shown. The plate 10 is used witha second plate 110 (see FIGS. 7 and 8) that may be substantially thesame or, alternatively, identical to the plate 10 to form a containerassembly that is releasably lockable.

It is contemplated that other container assemblies may be formed besidesthose using plates. For example, container assemblies may be formed, butare not limited to, using plates, bowls, platters, tubs, single-serveand family-size containers, single-serve and family-size ovenware, andcombinations thereof. One such combination is a bowl and a plate thatforms a container assembly. The remainder of the application willdiscuss container and container assemblies with respect to platesalthough it is recognized by one of ordinary skill in the art that othercontainer assemblies, such as those discussed above, may be formed.

The height and shape of the container assembly may vary from that shownwithout departing from the scope of the invention. For example, thecontainer assemblies of FIGS. 7 a and 14 a, as will be discussed, aredepicted as being generally circular. It is contemplated that thecontainer assemblies and containers used herein may be other shapes suchas rectangular, square, hexagonal, octagonal, other polygonal shapes, oroval.

The container assemblies of the present invention are typically usedwith respect to food, but may be used in other applications such as withmedical applications, cosmetics or other items. Food containerassemblies may be used for serving, storing, preparing and/or re-heatingthe food.

Referring back to FIGS. 1-2, the container 10 includes a continuous bodyportion 12 and a continuous rim 14 encompassing and projecting laterallyoutwardly from the body portion 12. The body portion 12 includes abottom 16 and a continuous sidewall 18 encompassing and projectingupwardly and outwardly from the bottom 16. It is contemplated that thesidewall may project only upwardly from the bottom 16 or even projectupwardly and inwardly from the bottom 16. It is also contemplated thatthe rim may not be continuous, although it is preferred to becontinuous.

Referring specifically to FIG. 2, the continuous rim 14 includes aplurality of ribs 20 that project generally upwardly therefrom. Theplurality of ribs 20 is spaced around the general periphery of thecontainer 10 and assists in forming a releasably lockable containerassembly. The orientation of the plurality of ribs 20 creates a patternthat is generally normal to the direction of the rim 14. Morespecifically, the orientation of the plurality of ribs 20 may create apattern that is normal to the direction of the rim 14. In a radialconfiguration with a pattern that is normal to the direction of the rim,each of the plurality of ribs 20, if extended inwardly, would passthrough the general center of the plate.

The plurality of ribs 20, however, may be formed in different patternsthan shown in FIG. 2 with respect to the rim 14 (e.g., diagonally). Itmay be desirable to form the plurality of ribs 20 in a decorativepattern for aesthetic reasons. Such a decorative feature may assist in“hiding” or disguising the releasable lockable feature in the container10. The container 10 of FIG. 2 has exactly 60 ribs formed in thecontinuous rim 14. It is contemplated that the number of ribs may varyfrom that shown in FIG. 2. For example, a container may have from about3 to about 10 ribs. A container may have greater than about 20 or about40 ribs, and may even have up to or greater than about 120 ribs. Thedesired number of ribs formed on the container will often vary dependingon factors such as the size or shape of the container assembly, thematerial(s) type and thicknesses of the container assembly, and thedesired holding strength of the container assembly. The desired holdingstrength depends on factors such as the weight of item(s) placed in thecontainer assembly and its perceived usage.

Turning to FIGS. 3-5, the plurality of ribs 20 is shown in greaterdetail. Specifically, a cross-sectional view of FIG. 3 shows twoadjacent ribs that project upwardly from the continuous rim 14. FIG. 3depicts a first rib 20 a and a second rib 20 b with a space 22 beingformed therebetween. The first rib 20 a of FIG. 3 comprises a generallyflat surface 24 that bridges two sidewalls 26, 28. The first rib 20 a isshown as being generally perpendicular to the plane of the remainder ofthe continuous rim 14. Specifically, the first rib 20 a is shown asbeing generally perpendicular to plane CC formed along the remainder ofthe rim 14 in FIG. 3. More specifically, the rib may be perpendicular tothe plane of the remainder of the rim. The sidewalls 26, 28 are spacedapart from each other and are shown as being generally perpendicular tothe plane CC of the remainder of the rim 14. The sidewalls 26, 28,however, do not necessarily have to be generally perpendicular orperpendicular to the remainder of the rim 14.

Similarly, second rib 20 b of FIG. 3 comprises a generally flat surface30 that bridges two sidewalls 32, 34. The second rib 20 b is also shownas being generally perpendicular to the plane CC of the remainder of therim 14. The sidewalls 32, 34 are spaced apart from each other and areshown as being generally perpendicular to the plane CC of the remainderof the rim 14.

To provide an improved locked container assembly, at least one of therib sidewalls may have an undercut. Such an optional undercut formed inthe rib sidewall engages a similar undercut in a corresponding spaceformed between adjacent ribs of a second container when the containerassembly is formed. This is discussed below in further detail withrespect to FIGS. 7-8. For example, in FIG. 3, optional undercuts 26 a,28 a are formed in respective sidewalls 26, 28. The size and shape ofthe undercut will often vary depending on factors such as the size orshape of the container assembly, the material(s) type and thicknesses ofthe container assembly, and the desired holding strength of thecontainer assembly. The desired holding strength may depend on factorssuch as the weight of item(s) placed in the container assembly and itsperceived usage.

The number of undercuts formed in the rib sidewalls, if any, depends onfactors such as the desired leak-resistant, the type of closuremechanism, manufacturability of the container assemblies, and thematerial(s) type and thicknesses used in forming the containerassemblies. For example, if the container assemblies are made of a firstmaterial that has a higher coefficient of friction than a secondmaterial, then the container made of the first material will likely needless undercuts in its sidewalls than the same container made with thesecond material to have the same holding strength. The number ofundercuts used also depends on the fitness of use of the containerassembly, including the holding strength thereof.

It is contemplated that the ribs may have sidewalls with no undercuts orat least one undercut (e.g., first rib 20 a with optional undercuts 26a, 28 a in FIG. 3). It is also contemplated that some ribs within thesame container may have no undercuts, while other ribs may have one ormore undercuts.

Referring to FIGS. 4 and 5, adjacent ribs 36, 38 of a portion of the rim14 are shown in more detail. In FIG. 4, a top view of the ribs 36, 38shows that the ribs 36, 38 generally taper inwardly toward the center ofthe container. FIG. 4 also shows a generally flat area 36 a of rib 36and a generally flat area 38 a of rib 38. To improve the sealability ofthe container assembly, the generally flat areas 36 a, 38 a may contactsimilar sized flat areas formed in the respective spaces betweenadjacent ribs of a second container that form the container assembly. Anexample of a similar sized flat area formed in a space between adjacentribs is shown in FIG. 4 with generally flat area 40.

FIG. 5 shows adjacent ribs 42, 44 with respective generally flat areas42 a, 44 a. The ribs 42, 44 are spaced apart with a generally flat area46 that is formed between generally flat areas 42 a, 44 a. To maintainclearances on radial designs (e.g., oval or circular shaped), thegenerally flat areas may grow proportionally with the diameter (i.e.,increase in size as the distance increases from the center of thecontainer). For example, in FIG. 5, the width W1 of generally flat area42 a may be smaller than width W2. With, for example, rectangular-shapedcontainers, the size of the generally flat areas typically remainsconstant as the distance increases from the center of the container. Itis contemplated that this area of the ribs may be sized and shapeddifferently than shown in FIGS. 4 and 5.

It is contemplated that the shape and size of the plurality of ribs 20may vary from that shown in FIGS. 2-5. It is preferred that theplurality of ribs be shaped and sized to minimize the stacking height ofthe containers used to form container assemblies. It is desirable tominimize the stacking height of the containers to (a) reducetransportation costs and packaging, and (b) provide space efficiency inretail and consumer settings. It is also desirable to maximize theholding strength of the container assembly. The desired holding strengthis often a balance between making the container assembly easy for aconsumer to open and close, while still preventing or inhibiting aninadvertent opening of the container assembly.

It is contemplated that the upwardly projecting features may be shapeddifferently than the ribs shown in FIGS. 2-5 and 11-13. For example, theupwardly projecting features may be a plurality of round, oval, square,or polygonal features. It is contemplated that many shapes and sizes maybe formed by the upwardly projecting features used in the presentinvention.

Referring to FIGS. 5 and 6, an optional seal feature 50 formed on therim 14 is depicted. In FIG. 6, the optional seal feature 50 is locatedoutwardly from the rib 52 with respect to the center of the container10. In other words, the optional seal feature 50 is located farther awayfrom the center of the container 10 than the rib 52. The optional sealfeature 50 in conjunction with a corresponding optional seal feature onanother container (not shown), along with the locked ribs of thecontainer assembly, assist in preventing or inhibiting material fromleaving or entering the container assembly. The optional seal feature isespecially useful in preventing or inhibiting product leakage that mayoccur due to tolerances within the manufacturing process. To provide anefficient seal, the height H1 of the optional seal feature 50 should beat least one-half of the rib height H2.

The optional seal feature, however, may be located inwardly from theribs such that the seal is formed nearer the center of the containerassembly as compared to the releasably lockable ribs. For example, inFIGS. 16 a and 16 b, a container 510 includes a plurality of ribs 520and also includes an optional seal feature 550. In FIGS. 6 and 16 b, theoptional seal feature 550 is located inwardly from the plurality of ribs520 with respect to the center of the container 510. The optional sealfeature 550 in conjunction with a corresponding seal feature on anothercontainer (not shown), along with the locked ribs of the containerassembly, assist in preventing or inhibiting material from leaving orentering the container assembly. The optional seal feature may be formedin a variety of shapes, including a general conical shape.

A container assembly 100 according to one embodiment of the presentinvention is depicted in FIGS. 7 a, 7 b. The container 100 comprises thefirst container 10 and a second container 110. In one embodiment, thesecond container 110 is shaped substantially the same as the firstcontainer 10. Alternatively, the second container 110 may be identicalto the first container 10. It may be desirable to have containersidentically shaped to reduce waste by a consumer when the top containeror lid is not used. As discussed above, the container assembly may beformed with different first and second containers than plates.

The container assembly 100 of FIGS. 7 a, 7 b may be formed according toone method by providing the first container 10 and the second container110. The second container 110 includes a continuous body portion 112 anda continuous rim 114 that encompasses and projects laterally outwardlyfrom the body portion 112. Similarly, the first container 10, asdiscussed above, includes the continuous body portion 12 and thecontinuous rim 14 that encompasses and projects laterally outwardly fromthe body portion 12. Both of the rims 14, 114 include a respectiveplurality of ribs with spaces therebetween (not shown in FIGS. 7 a, 7b). Each of the plurality of ribs may be shaped and sized similarly tothe ribs 20 shown above in FIGS. 2-5. Each of the plurality of ribsprojects generally upwardly therefrom (i.e., in a direction away fromthe continuous body portion).

The second container 110 is flipped 180 degrees relative to the firstcontainer 10 such that the containers 10, 110 are generally aligned andthe rims 14, 114 are adjacent to each other. This flipped position ofcontainer 110 relative to the container 10 is shown in FIG. 7 a. To fitthe ribs into respective spaces, the container 110 may have to berotated slightly such that the ribs are offset (i.e., the ribs andspaces are aligned). It is desirable that the consumer can assembly thecontainers so as to form a container assembly of the present invention.

Referring to FIG. 8, adjacent ribs 120 a, 120 b of the container 110 arefit into respective second spaces 22 a, 22 b of the container 10 andribs 20 a, 20 b of the container 10 are fit into respective spaces 122a, 122 b such that the container assembly 100 is releasably lockable. Tofit the ribs into respective spaces, the container 110 may have to berotated slightly such that the ribs are offset (i.e., the ribs andspaces are aligned). FIG. 8 also depicts interference areas 124 a, 124 bformed between the first rib 20 a and the space 122 a created betweenribs 120 a, 120 b of the container 110.

The strength of this lockable closure is dependent on many variablessuch as the number of the projecting ribs, the height of those ribs,whether undercuts are included, the size of the contact areas, theclearance needed between spaces and ribs, and the material(s) type andthickness used in forming the container assemblies. To improve thelockability of the container assembly, as discussed above, an optionalsealing feature may be added.

Referring to FIGS. 9-10, a container (e.g., plate 210) includes acontinuous body portion 212 and a continuous rim 214 encompassing andprojecting laterally outwardly from the body portion 212. The bodyportion 212 includes a bottom 216 and a continuous sidewall 218encompassing and projecting upwardly and outwardly from the bottom 216.It is contemplated that the sidewall may project only upwardly from thebottom 216 or even project upwardly and inwardly from the bottom 216. Itis also contemplated that the rim may not be continuous, although it ispreferred to be continuous.

Referring to FIGS. 10 and 11, the continuous rim 214 includes aplurality of rib sets 220 that project generally upwardly therefrom. Theplurality of rib sets 220 is spaced around the general periphery of thecontainer 210 and assists in forming a releasably lockable containerassembly. The orientation of the plurality of rib sets 220 creates apattern that is generally parallel or generally concentric with thegeneral direction of the rim 214. In other words, each of the pluralityof rib sets 220, if extended outwardly, would be no closer to thegeneral center of the container 210. The plurality of rib sets 220 is inthe opposite direction of the plurality of ribs 20 in FIGS. 2-5.

The plurality of rib sets 220, however, may be formed in differentpatterns than shown in FIG. 10 with respect to the rim 214 (e.g.,diagonally). It may be desirable to form the plurality of rib sets 220in a decorative pattern for aesthetic reasons. Such a decorative featuremay assist in “hiding” or disguising the releasable lockable feature inthe container 210.

The container 210 of FIG. 10 has exactly 60 sets of ribs formed in thecontinuous rim 214. As will be discussed in more detail below, each ofthe plurality of rib sets 220 has a first set of ribs on a raisedportion and a second set of ribs on a recessed portion. It iscontemplated that the number of rib sets may vary from that shown inFIG. 10. For example, a container may have from about 2 to about 30 setsof ribs. A container may have greater than about 40 or about 80 sets ofribs, and may even have up to or greater than about 120 sets of ribs.The desired number of ribs formed on the container will often varydepending on factors such as the size or shape of the containerassembly, the material(s) type and thicknesses of the containerassembly, and the desired holding strength of the container assembly.The desired holding strength may depend on factors such as the weight ofitem(s) placed in the container assembly and its perceived usage.

Turning to FIGS. 11-13, two adjacent sets of ribs are shown in greaterdetail. The number of ribs in a set varies in FIGS. 11 and 12 dependingon whether the ribs are located in a recessed area or a raised areaformed in the rim 214. For example, in FIGS. 11 and 12, recessed area240 has a first rib 242 and a second rib 244 with spaces 246, 248 and250. Raised area 260 of FIGS. 11 and 12, however, has a first rib 262, asecond rib 264, and a third rib 266 with spaces 268, 270 therebetween.Each of the ribs of FIGS. 11 and 12 projects upwardly from thecontinuous rim 214.

Referring specifically to FIG. 13, a cross-sectional view of therecessed area 240 is depicted and includes the ribs 242, 244. Across-sectional view of the raised area 260 (not shown) would depictthree ribs. The first rib 242 of FIG. 13 comprises a generally flatsurface 288 that bridges two sidewalls 290, 292. The first rib 242 isshown as being generally perpendicular to the plane of the remainder ofthe continuous rim 214. Specifically, the first rib 242 is shown asbeing generally perpendicular to plane DD formed along the remainder ofthe rim 214 in FIG. 13. More specifically, the rib may be perpendicularto the plane of the remainder of the rim. The sidewalls 290, 292 arespaced apart from each other and are shown as being generallyperpendicular to the plane DD of the remainder of the rim 214. Thesidewalls 290, 292, however, do not necessarily have to be generallyperpendicular or perpendicular to the remainder of the rim 214.

Similarly, second rib 244 of FIG. 13 comprises a generally flat surface298 that bridges two sidewalls 300, 302. The second rib 244 is alsoshown as being generally perpendicular to the plane DD of the remainderof the rim 214. The sidewalls 300, 302 are spaced apart from each otherand are shown as being generally perpendicular to the plane DD of theremainder of the rim 214.

To provide an improved locked container assembly, at least one of therib sidewalls may have an optional undercut. As discussed above, such anundercut formed in the rib sidewall engages a similar undercut in thespaces formed between adjacent ribs when the container assembly isformed. For example, in FIG. 13, optional undercuts 290 a, 292 a areformed in respective sidewalls 290, 292. The size and shape of theundercut will often vary depending on factors such as the size or shapeof the container assembly, the material(s) type and thicknesses of thecontainer assembly, and the desired holding strength of the containerassembly. The desired holding strength may depend on factors such as theweight of item(s) placed in the container assembly and its perceivedusage.

As discussed above, the number of undercuts formed in the rib sidewalls,if any, depends on several factors. It is contemplated that the ribs mayhave sidewalls with no undercuts or at least one undercut (e.g., firstrib 242 with optional undercuts 290 a, 292 a in FIG. 13). It is alsocontemplated that some ribs within the same container may have noundercuts, while other ribs have one or more undercuts.

Referring back to FIG. 12, the raised and recessed areas 240, 260 have aplurality of ribs with generally flat areas. For example, the rib 242includes a top surface or generally flat area 242 a. Similarly, the rib264 includes a top surface or generally flat area 264 a. To improve thesealability of the container assembly, the generally flat areas 264 a,242 a may contact similar sized flat areas formed in the spaces formedbetween adjacent ribs of a second container that forms the containerassembly. An example of a similar sized flat area formed in a space isdepicted in FIG. 12 with space 246. As shown in FIG. 12, a generallyflat area 282 is formed between adjacent sets of ribs (i.e., the raisedand recessed portions) to assist in releasably locking the containerassembly. It is contemplated that this area of the ribs may be sized andshaped differently than shown in FIGS. 11-13. It is contemplated thatthe numbers of ribs in a set of ribs may vary from that shown in FIGS.11 and 12 (two ribs in the recessed areas and three ribs in the raisedareas)

It is contemplated that the shape and size of the plurality of ribs 220may vary from that shown in FIGS. 10-13. It is preferred that theplurality of ribs be shaped and sized to minimize the stacking height ofthe containers. It is desirable to minimize the stacking height of thecontainers to (a) reduce transportation costs and packaging, and (b)provide space efficiency in retail and consumer settings. It is alsodesirable to maximize the holding strength of the container assembly.The desired holding strength is often a balance between making thecontainer assembly easy for a consumer to open and close, while stillpreventing or inhibiting an inadvertent opening of the containerassembly.

Referring specifically to FIG. 12, an optional seal feature 350 formedon the rim 214 is depicted. The optional seal feature 350 is locatedoutwardly from the ribs 242, 244, 262, 264 and 266 with respect to thecenter of the container 210. In other words, the optional seal feature350 is located farther away from the center of the container 210 thanthe ribs. The optional seal feature 350 in conjunction with acorresponding seal feature on another container (e.g. optional sealfeature 450 shown in FIG. 15), along with the locked ribs of thecontainer assembly, assist in preventing or inhibiting material fromleaving or entering the container assembly. The optional seal feature isespecially useful in preventing or inhibiting product leakage that mayoccur due to tolerances within the manufacturing process. To provide anefficient seal, the height of the optional seal feature should be atleast one-half of the rib height. This is shown in FIG. 15 where theoptional seal features 350 and 450 contact each other.

As discussed above with respect to FIGS. 16 a, b above, the optionalseal feature, however, may be located inwardly from the ribs such thatthe seal is formed nearer the center of the container assembly ascompared to the releasably lockable ribs.

A container assembly 400 according to one embodiment of the presentinvention is depicted in FIGS. 14 a, 14 b. The container 400 comprisesthe first container 210 and a second container 410. In one embodiment,the second container 410 is shaped substantially the same as the firstcontainer 210. Alternatively, the second container 410 may be identicalto the first container 210. As discussed above, the container assemblymay be formed with different first and second containers than plates.For example, the container assembly may be formed using a bowl and aplate.

The container assembly 400 of FIGS. 14 a, 14 b may be formed accordingto one method by providing the first container 210 and the secondcontainer 410. The second container 410 includes a continuous bodyportion 412 and a continuous rim 414 that encompasses and projectslaterally outwardly from the body portion 412. Similarly, the firstcontainer 210, as discussed above, includes the continuous body portion212 and the continuous rim 214 that encompasses and projects laterallyoutwardly from the body portion 212. Both of the rims 214, 414 include arespective plurality of ribs with spaces therebetween (not shown inFIGS. 14 a, 14 b). Each of the plurality of ribs may be shaped and sizedsimilarly to the ribs 220 shown above in FIGS. 10-13. Each of theplurality of ribs projects generally upwardly therefrom (i.e., in adirection away from the continuous body portion).

As discussed above with container assembly 100, the second container 410is flipped 180 degrees relative to the first container 210 such that thecontainers 210, 410 are generally aligned and the rims 214, 414 areadjacent to each other. This flipped position of the container 410relative to the container 210 is shown in FIG. 14 a.

Referring to FIG. 15, adjacent ribs 262, 264, 266 of one set of thecontainer 210 are fit into respective second spaces 422, 424, and 426 ofthe container 410 and ribs 418, 420 of the container 410 are fit intorespective spaces 268, 270 such that the container assembly 400 isreleasably lockable.

Referring to FIGS. 17-21, a container (e.g., plate 610) to be used in afurther embodiment of the present invention is shown. The plate 610 isused with a second plate 710 (see FIGS. 22 and 23) that may besubstantially the same or, alternatively, identical to the plate 610 toform a container assembly that is releasably lockable.

Referring to FIGS. 17-18, the container 610 includes a continuous bodyportion 612 and a continuous rim 614 encompassing and projectinglaterally outwardly from the body portion 612. The body portion 612includes a bottom 616 and a continuous sidewall 618 encompassing andprojecting upwardly and outwardly from the bottom 616. It iscontemplated that the sidewall may project only upwardly from the bottom616 or even project upwardly and inwardly from the bottom 616. It isalso contemplated that the rim may not be continuous, although it ispreferred to be continuous. Optional handle portions 652 are included onthe container 610 to assist the users ability to utilize the container610.

Referring specifically to FIG. 18, the continuous rim 614 includes aplurality of ribs 620 that project generally upwardly therefrom. Theplurality of ribs 620 is spaced around the general periphery of thecontainer 610 and assists in forming a releasably lockable containerassembly. The orientation of the plurality of ribs 620 creates a patternthat is generally normal to the direction of the rim 614. Morespecifically, the orientation of the plurality of ribs 620 may create apattern that is normal to the direction of the rim 614. In a radialconfiguration with a pattern that is normal to the direction of the rim,each of the plurality of ribs 620, if extended inwardly, would passthrough the general center of the plate.

The plurality of ribs 620, however, may be formed in different patternsthan shown in FIG. 18 with respect to the rim 614 (e.g., diagonally).The container 610 of FIG. 18 has exactly 44 ribs formed in thecontinuous rim 614. It is contemplated that the number of ribs may varyfrom that shown in FIG. 18. For example, a container may have from about3 to about 10 ribs. A container generally has from about 20 ribs toabout 60 ribs. Containers typically have from about 30 ribs to about 50ribs. The desired number of ribs formed on the container will often varydepending on factors such as the size or shape of the containerassembly, the material(s) type and thicknesses of the containerassembly, and the desired holding strength of the container assembly.The desired holding strength depends on factors such as the weight ofitem(s) placed in the container assembly and its perceived usage.

Turning to FIGS. 19-21, the plurality of ribs 620 is shown in greaterdetail. Specifically, a cross-sectional view of FIG. 19 shows twoadjacent ribs that project upwardly from the continuous rim 614. FIG. 19depicts a first rib 620 a and a second rib 620 b with a space 622 beingformed therebetween. The first rib 620 a of FIG. 19 comprises agenerally flat surface 624 that bridges two sidewalls 626, 628. Thefirst rib 620 a is shown as being generally perpendicular to the planeof the remainder of the continuous rim 614. Specifically, the first rib620 a is shown as being generally perpendicular to plane EE formed alongthe remainder of the rim 614 in FIG. 19. More specifically, the rib maybe perpendicular to the plane of the remainder of the rim. The sidewalls626, 628 are spaced apart from each other and are shown as beinggenerally perpendicular to the plane EE of the remainder of the rim 14.The sidewalls 626, 628, however, do not necessarily have to be generallyperpendicular or perpendicular to the remainder of the rim 14.

Similarly, second rib 620 b of FIG. 19 comprises a generally flatsurface 630 that bridges two sidewalls 632, 634. The second rib 620 b isalso shown as being generally perpendicular to the plane EE of theremainder of the rim 614. The sidewalls 632, 634 are spaced apart fromeach other and are shown as being generally perpendicular to the planeEE of the remainder of the rim 614.

To provide an improved locked container assembly, at least one of therib sidewalls may have an undercut. Such an optional undercut formed inthe rib sidewall engages a similar undercut in a corresponding spaceformed between adjacent ribs of a second container when the containerassembly is formed. This is discussed below in further detail withrespect to FIGS. 22-24. For example, in FIG. 19, optional undercuts 626a, 628 a are formed in respective sidewalls 626, 628. The size and shapeof the undercut will often vary depending on factors such as the size orshape of the container assembly, the material(s) type and thicknesses ofthe container assembly, and the desired holding strength of thecontainer assembly. The desired holding strength may depend on factorssuch as the weight of item(s) placed in the container assembly and itsperceived usage.

The number of undercuts formed in the rib sidewalls, if any, depends onfactors such as the desired holding strength, the desiredleak-resistant, the type of closure mechanism, manufacturability of thecontainer assemblies, and the material(s) type and thicknesses used informing the container assemblies. For example, if the containerassemblies are made of a first material that has a higher coefficient offriction than a second material, then the container made of the firstmaterial will likely need less undercuts in its sidewalls than the samecontainer made with the second material to have the same holdingstrength. The number of undercuts used also depends on the fitness ofuse for a particular application of the container assembly, includingthe holding strength thereof.

It is contemplated that the ribs may have sidewalls with no undercuts orat least one undercut (e.g., first rib 620 a with optional undercuts 626a, 628 a in FIG. 19). It is also contemplated that some ribs within thesame container may have no undercuts, while other ribs may have one ormore undercuts.

Referring to FIG. 20, adjacent ribs 642, 644 of a portion of the rim 614are shown in more detail. FIG. 20 shows adjacent ribs 642, 644 withrespective generally flat areas 642 a, 644 a. The ribs 642, 644 arespaced apart with a generally flat area 646 that is formed betweengenerally flat areas 642 a, 644 a.

In FIG. 21, a top view of the ribs 636, 638 shows that the ribs 636, 638generally taper inwardly toward the center of the container. FIG. 21also shows a generally flat area 636 a of rib 636 and a generally flatarea 638 a of rib 638. To improve the sealability of the containerassembly, the generally flat areas 636 a, 638 a may contact similarsized flat areas formed in the respective spaces between adjacent ribsof a second container that form the container assembly. An example of asimilar sized flat area formed in a space between adjacent ribs is shownin FIG. 21 with generally flat area 640. A rounded portion 654transitions from the generally flat areas 636 a, 638 a of the ribs 636,638 towards the body portion 612 of the container 610. The roundedportion 654 assists the operability of the container assembly that isreleasably lockable. The rounded portion 654 eases the alignment of theribs with their respective spaces as shown in FIG. 24, by allowing theribs to slide into their respective spaces when forming a containerassembly.

It is contemplated that the shape and size of the plurality of ribs 620may vary from that shown in FIGS. 18-21. It is preferred that theplurality of ribs be shaped and sized to minimize the stacking height ofthe containers used to form container assemblies. It is desirable tominimize the stacking height of the containers to (a) reducetransportation costs and packaging, and (b) provide space efficiency inretail and consumer settings. It is also desirable to maximize theholding strength of the container assembly. The desired holding strengthis often a balance between making the container assembly easy for aconsumer to open and close, while still preventing or inhibiting aninadvertent opening of the container assembly.

Referring back to FIG. 20, an optional seal feature 650 formed on therim 614 is depicted. In FIG. 20, the optional seal feature 650 islocated outwardly from the ribs 642, 644 with respect to the center ofthe container 610. In other words, the optional seal feature 650 islocated farther away from the center of the container 610 than the ribs642, 644. The optional seal feature 650 in conjunction with acorresponding optional seal feature on another container (not shown),along with the locked ribs of the container assembly, assist inpreventing or inhibiting material from leaving or entering the containerassembly. The optional seal feature is especially useful in preventingor inhibiting product leakage that may occur due to tolerances withinthe manufacturing process. To provide an efficient seal, the height ofthe optional seal feature 650 should be at least one-half of the ribheight.

The optional seal feature, however, may be located inwardly from theribs such that the seal is formed nearer the center of the containerassembly as compared to the releasably lockable ribs. The optional sealfeature may be formed in a variety of shapes, including a generalconical shape.

A container assembly 700 according to one embodiment of the presentinvention is depicted in FIGS. 22, 23. The container assembly 700comprises the first container 610 and a second container 710. In oneembodiment, the second container 710 is shaped substantially the same asthe first container 610. Alternatively, the second container 710 may beidentical to the first container 610. It may be desirable to havecontainers identically shaped to reduce waste by a consumer when the topcontainer or lid is not used. As discussed above, the container assemblymay be formed with different first and second containers than plates.

The container assembly 700 of FIGS. 22, 23 may be formed according toone method by providing the first container 610 and the second container710. The second container 710 includes a continuous body portion 712 anda continuous rim 714 that encompasses and projects laterally outwardlyfrom the body portion 712. Similarly, the first container 610, asdiscussed above, includes the continuous body portion 612 and thecontinuous rim 614 that encompasses and projects laterally outwardlyfrom the body portion 612. Both of the rims 614, 714 include arespective plurality of ribs with spaces therebetween (not shown inFIGS. 22, 23). Each of the plurality of ribs may be shaped and sizedsimilarly to the ribs shown above in FIGS. 18-21. Each of the pluralityof ribs projects generally upwardly therefrom (i.e., in a direction awayfrom the continuous body portion).

The second container 710 is flipped 180 degrees relative to the firstcontainer 610 such that the containers 610, 710 are generally alignedand the rims 614, 714 are adjacent to each other. This flipped positionof container 710 relative to the container 610 is shown in FIG. 22. Tofit the ribs into respective spaces, the container 710 may have to berotated slightly such that the ribs are offset (i.e., the ribs andspaces are aligned). It is desirable that the consumer can assembly thecontainers so as to form a container assembly of the present invention.

Referring to FIG. 24, adjacent ribs 720 a, 720 b of the container 710are fit into respective second spaces 622 a, 622 b of the container 610and ribs 620 a, 620 b of the container 610 are fit into respectivespaces 722 a, 722 b such that the container assembly 700 is releasablylockable. To fit the ribs into respective spaces, the container 710 mayhave to be rotated slightly such that the ribs are offset (i.e., theribs and spaces are aligned). FIG. 24 also depicts interference areas724 a, 724 b formed between the first rib 620 a and the space 722 acreated between ribs 720 a, 720 b of the container 710.

The strength of this lockable closure is dependent on many variablessuch as the number of the projecting ribs, the height of those ribs,whether undercuts are included, the size of the contact areas, theclearance needed between spaces and ribs, and the material(s) type andthickness used in forming the container assemblies. To improve thelockability of the container assembly, as discussed above, an optionalsealing feature may be added.

The strength of this lockable closure is dependent on many variablessuch as the number of the projecting ribs, the height of those ribs,whether undercuts are included, the size of the contact areas, theclearance needed between spaces and ribs, and the material(s) type andthickness used in forming the container assemblies. To improve thelockability of the container assembly, as discussed above, an optionalsealing feature may be added.

The container assemblies of the present invention are typically formedfrom polymeric materials, but may be formed from materials such as paperor metal. The polymeric containers may be formed from polyolefins. Thepolymeric food containers are typically formed from orientatedpolystyrene (OPS), polyethylene terephthalate (PET), high-impactpolystyrenes (HIPS), polyvinyl chloride (PVC), polypropylene andcombinations thereof. The containers assemblies may be made from amineral-filled polymeric material such as, for example, talc or calciumcarbonate-filled polyolefin. An example of paper that may be used informing the container assemblies is paperboard or molded fiber.Paperboard and molded fiber typically have a sufficient coefficient offriction to maintain the first and second containers in a lockableposition.

As discussed, the materials used in forming the container assembly mayassist in releasably locking the container assembly. For example, thematerial(s) forming the container assembly may have a fairly tackylaminate on one side that corresponds with a fairly tacky laminate onthe opposing side, resulting in a desirable releasably lockablecontainer assembly.

It is contemplated that the containers used in forming the containerassemblies may be made from different materials. It is contemplated thatone of ordinary skill in the art will recognize that other polymers orcombination of polymers may be used to form the containers.

The container assemblies of the present invention are typicallydisposable, but it is contemplated that they may be reused at a futuretime. The containers used in forming the container assemblies (e.g.,container 10) are shown as including one compartment. It is contemplatedthat the containers may be formed of multiple compartments. Suchcontainers are desirable for placing items (e.g., food items) indifferent compartments to prevent or inhibit commingling of items. Forexample, undesirable mixing of food items can corrupt the flavor and theconsistency of the food items.

As discussed above, the container assemblies may be used with fooditems. A method of using such container assemblies includes placing thefood and locking the containers to form a container assembly with foodtherein. The container assembly is then placed in a heating apparatusand heated. Typical heating apparatuses include microwaves andconventional ovens. The container assemblies may contain solid foodproducts. The container assemblies may be used for storage in therefrigerator and/or the freezer.

The containers to be used in forming the container assemblies of thepresent invention may be formed using conventional thermoforming (e.g.,by pressure, vacuum or the combination thereof), injection-moldingprocesses, or rotational molding. According to one method ofthermoforming, pellets of a polymeric resin and additives, if any, areadded into an extruder. The pellets of the polymeric resin andadditives, if any, are melted to form a blend. The blend is extrudedthrough a die to form an extruded sheet. The extruded sheet isthermoformed to a desired shape of a container to be used in forming thecontainer assembly.

The thickness of the container to be used in forming the containerassemblies generally ranges from about 0.002 to about 0.15 inch, but istypically from about 0.005 to about 0.04 inch. The container assembliesmay be opaque or a variety of colors or color combinations. Thecontainer assemblies typically have at least one transparent containerif it is desired for the customer to ascertain the nature of theaccommodated product and the condition thereof without having to openthe container assembly.

While particular embodiments and applications of the present inventionhave been illustrated and described, it is to be understood that theinvention is not limited to the precise construction and compositionsdisclosed herein and that various modifications, changes, and variationsmay be apparent from the foregoing descriptions without departing fromthe spirit and scope of the invention as defined in the appended claims.

1. A container assembly, comprising: a first container including a firstcontinuous body portion and a first rim, the first rim encompassing andprojecting laterally outwardly from the first body portion, the rimhaving a first plurality of ribs projecting generally upwardly therefromsuch that first spaces are formed between adjacent ribs, the firstplurality of ribs having a first sidewall and a second sidewall and agenerally flat surface that encompasses and bridges the first and secondsidewalls, the first plurality of ribs having a rounded portiontransitioning from the generally flat surface towards the first bodyportion; a second container including a second continuous body portionand a second rim, the second rim encompassing and projecting laterallyoutwardly from the second body portion, the rim having a secondplurality of ribs projecting generally upwardly therefrom such thatsecond spaces are formed between adjacent ribs, the second plurality ofribs having a third sidewall and a fourth sidewall and a generally flatsurface that encompasses and bridges the first and second sidewalls, thesecond plurality of ribs having a rounded portion transitioning from thegenerally flat surface towards the second body portion, the secondcontainer being shaped substantially the same as the second container;and wherein the first container and the second container are adapted tobe releasably lockable to each other by fitting the first plurality ofupwardly-projecting ribs into respective second spaces and fitting thesecond plurality of upwardly-projecting ribs into respective firstspaces.
 2. The container assembly of claim 1, wherein the first andsecond containers are bowls.
 3. The container assembly of claim 1,wherein the first and second containers are plates.
 4. The containerassembly of claim 1, wherein the first container is a bowl and thesecond container is a plate.
 5. The container assembly of claim 1,wherein the first and second containers are made of polymeric material.6. The container assembly of claim 5, wherein the first and secondcontainers are made of a mineral-filled polymeric material.
 7. Thecontainer assembly of claim 5, wherein the first and second containersare made of high-impact polystyrene.
 8. The container assembly of claim1, wherein at least one of the first and second containers are paper ormetal.
 9. The container assembly of claim 1, wherein the first containeris identical to the second container.
 10. The container assembly ofclaim 1, wherein the first plurality of upwardly-projecting ribs and thesecond plurality of upwardly-projecting ribs are generally perpendicularto the plane of the remainder of the respective rims.
 11. The containerassembly of claim 1, wherein at least one of the first and secondsidewalls of the first plurality of upwardly-projecting ribs has a firstundercut, and wherein at least one of the third and fourth sidewalls ofthe second plurality of upwardly-projecting ribs has a second undercut.12. The container assembly of claim 1, wherein each of the firstplurality of upwardly-projecting ribs and the second plurality ofupwardly-projecting ribs includes at least about 3 ribs.
 13. Thecontainer assembly of claim 12, wherein each of the first plurality ofupwardly-projecting ribs and the second plurality of upwardly-projectingribs includes at least about 40 ribs.
 14. The container assembly ofclaim 1, wherein the first rim and the second rim are adapted to form aseal.
 15. The container assembly of claim 14, wherein the seal islocated outwardly from the first plurality of upwardly-projecting ribsand the second plurality of upwardly-projecting ribs.
 16. The containerassembly of claim 14, wherein the seal is located inwardly from thefirst plurality of upwardly-projecting ribs and the second plurality ofupwardly-projecting ribs.
 17. The container assembly of claim 1, whereinthe first container has at least one handle portion, and the secondcontainer has at least one handle portion.
 18. A container assembly,comprising: a first container including a first continuous body portionand a first rim, the first rim encompassing and projecting laterallyoutwardly from the first body portion, the rim having a first pluralityof ribs projecting generally upwardly therefrom such that first spacesare formed between adjacent ribs, the first plurality of ribs having afirst sidewall and a second sidewall and a generally flat surface thatencompasses and bridges the first and second sidewalls, the firstplurality of ribs having a rounded portion transitioning from thegenerally flat surface towards the first and second sidewalls; and asecond container including a second continuous body portion and a secondrim, the second rim encompassing and projecting laterally outwardly fromthe second body portion, the rim having a second plurality of ribsprojecting generally upwardly therefrom such that second spaces areformed between adjacent ribs, the second plurality of ribs having athird sidewall and a fourth sidewall and a generally flat surface thatencompasses and bridges the third and fourth sidewalls, the secondplurality of ribs having a rounded portion transitioning from thegenerally flat surface towards the third and fourth sidewalls, thesecond rim and the first rim being shaped substantially the same;wherein the first container and the second container are adapted to bereleasably lockable to each other by fitting the first plurality ofupwardly-projecting ribs into respective second spaces and fitting thesecond plurality of upwardly-projecting ribs into respective firstspaces.
 19. The container assembly of claim 18, wherein the first andsecond containers are made of polymeric material.
 20. The containerassembly of claim 19, wherein the first and second containers are madeof a mineral-filled polymeric material.
 21. The container assembly ofclaim 19, wherein the first and second containers are made ofhigh-impact polystyrene.
 22. The container assembly of claim 18, whereinthe first rim is identical to the second rim.
 23. The container assemblyof claim 18, wherein the first plurality of upwardly-projecting ribs andthe second plurality of upwardly-projecting ribs are generallyperpendicular to the plane of the remainder of the respective rims. 24.The container assembly of claim 18, wherein at least one of the firstand second sidewalls of the first plurality of upwardly-projecting ribshas a first undercut, and wherein at least one of the third and fourthsidewalls of the second plurality of upwardly-projecting ribs has asecond undercut.
 25. The container assembly of claim 18, wherein each ofthe first plurality of upwardly-projecting ribs and the second pluralityof upwardly-projecting ribs includes at least about 3 ribs.
 26. Thecontainer assembly of claim 25, wherein each of the first plurality ofupwardly-projecting ribs and the second plurality of upwardly-projectingribs includes at least about 40 ribs.
 27. The container assembly ofclaim 18, wherein the first rim and the second rim are adapted to form aseal.
 28. A container to be used in a container assembly, comprising acontinuous body portion and a rim, the rim encompassing and projectinglaterally outwardly from the body portion, the rim having a firstplurality of ribs projecting generally upwardly therefrom such thatfirst spaces are formed between adjacent ribs, the first plurality ofribs having a first sidewall and a second sidewall and a generally flatsurface that encompasses and bridges the first and second sidewalls, thefirst is plurality of ribs having a rounded portion transitioning fromthe generally flat surface towards the first body portion, the rim beingadapted to be releasably lockable by fitting the first plurality of ribsand first spaces into respective second spaces and second plurality ofribs of a second container, the second container being shapedsubstantially the same as the first container.
 29. The container ofclaim 28, wherein the first container is a bowl.
 30. The container ofclaim 28, wherein the first container is a plate.
 31. The container ofclaim 28, wherein the first container is made of polymeric material. 32.The container of claim 28, wherein the first container is made ofhigh-impact polystyrene.
 33. The container of claim 28, wherein at leastone of the first and second sidewalls of the first plurality of ribs hasa first undercut.
 34. The container of claim 28, wherein the firstplurality of upwardly-projecting ribs includes at least about 20 ribs.35. A container to be used in a container assembly, comprising acontinuous body portion and a rim, the rim encompassing and projectinglaterally outwardly from the body portion, the rim having a firstplurality of ribs projecting generally upwardly therefrom such thatfirst spaces are formed between adjacent ribs, the first plurality ofribs having a first sidewall and a second sidewall and a generally flatsurface that encompasses and bridges the first and second sidewalls, thefirst plurality of ribs having a rounded portion transitioning from thegenerally flat surface towards the first and second sidewalls, the rimbeing adapted to be releasably lockable by fitting the first pluralityof ribs and first spaces into respective second spaces and secondplurality of ribs of a second container, the second container beingshaped substantially the same as the first container.
 36. The containerof claim 35, wherein the first container is made of polymeric material.37. The container of claim 36, wherein the first container is made ofhigh-impact polystyrene.
 38. The container of claim 35, wherein at leastone of the first and second sidewalls of the first plurality of ribs hasa first undercut.
 39. The container of claim 35, wherein the firstplurality of upwardly-projecting ribs includes at least about 20 ribs.